JP2979810B2 - Control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that outputs a fuel injection command signal, an ignition command signal, and the like by detecting a crank angle.

[0002]

2. Description of the Related Art Conventionally, a control device for an internal combustion engine has been
-49044. This device is
For a signal rotor that rotates in synchronization with the engine crankshaft
Detected objects for crank angle detection are set at equal intervals by the number of cylinders.
And a predetermined object to be detected for detecting a crank angle.
To divide one of the following intervals into unequal intervals
A reference position detecting object is provided, as shown in FIG.
Three time intervals of the passing signal (N signal) of the detected object
(T_i-2, T_i-1, T_i) By T_i-2・ T_i/ T _i-1
^Two> When the constant k is established, cylinder discrimination is performed, and fuel injection control and point
It controls the fire timing. In this way, using three information
This makes it possible to accurately determine the cylinder. When
Rollers start injection / ignition after cylinder discrimination in this way
In such cases, before discriminating the cylinder when starting the engine,
Cannot perform fuel injection and ignition, and
It becomes a problem. Therefore, as shown in FIG.
Therefore, two information (two time intervals)
T_i-1, T_i), T_i-1/ T_i<For the establishment of the constant k
Cylinder determination as shown in FIG.
With the input of the passing signal of the object for angle detection,
Detected object for crank angle detection to output injection command signal
Time interval T of the passing signal of_iIs 1/4 of the mask interval
If a signal enters this section, it will be invalidated and
Erroneous injection due to passing signal (additional pulse) of the position detection target
It is designed to prevent firing and misfires.

[0003]

However, before the cylinder discrimination based on the three pieces of information (before capturing the entire rotation fluctuation pattern).
When the rotation fluctuation becomes extremely large, such as an explosion → a misfire, a method such as cylinder discrimination based on two pieces of information or masking of an additional pulse causes a malfunction. That is, as shown in FIG. 14, when an explosion → misfire occurs, the rotation drops at the time of misfire, so that the pulse interval T _i0 becomes longer, and as a result, the mask interval (T
_i0 / 4) becomes longer, and the pulse for detecting the crank angle is also masked, so that no fuel injection command signal is output and no fuel injection is performed.

An object of the present invention is to provide a control device for an internal combustion engine that can achieve both startability and cylinder discrimination.

[0005]

SUMMARY OF THE INVENTION The present invention provides a crank angle detecting object provided on a signal rotor which rotates in synchronization with a crank shaft of an internal combustion engine, and a crank angle detecting object following the crank angle detecting object. A reference position detection target provided on the signal rotor so as to divide the interval into unequal intervals; and a passage detection unit for detecting passage of the detection target. In a control device for an internal combustion engine, which receives a passing signal and detects the passage of a reference position detecting object based on a time interval between the signals, an object passing signal by the passage detecting means after engine start is started. Detection required for cylinder discrimination after input
The gist of the present invention is a control device for an internal combustion engine which outputs a command signal for injecting fuel into all cylinders of the internal combustion engine in response to the input of the detected object passage signal from a point in time when a predetermined number smaller than the number is input.

It is preferable that an ignition command signal is output from a point in time when a predetermined number of passage signals of the crank angle detecting object are input after the output of the fuel injection command signal.

[0007]

In a state in which the passage of the detected object for reference position detection cannot be detected due to the time interval between the detected object passing signals after the start of the engine, the passage detection means discriminates the cylinder after the input of the detected object passing signal. Less than the number of detections required
From a point in time when a predetermined number is input, a fuel injection command signal to all cylinders of the internal combustion engine is output in accordance with the input of the detected object passage signal. That is, erroneous injection is prevented by not performing fuel injection until a time when there is no influence of the explosion → misfire shown in FIG.

When a predetermined number of passing signals of the object to be detected for detecting the crank angle are input after the output of the fuel injection command signal, that is, for example, after two strokes in a four-cycle engine,
An ignition command signal is output. As a result, it is possible to avoid an adverse effect due to the air-fuel mixture in the cylinder before the fuel injection.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a control device for an internal combustion engine according to the present embodiment, in which a four-cylinder four-cycle gasoline engine is mounted on an automobile.

A signal rotor 1 that rotates in synchronization with the camshaft is fixed to a camshaft of the engine. In the present embodiment, one rotation of the signal rotor 1 corresponds to two rotations of the crankshaft.

On the outer peripheral surface of the signal rotor 1, four projections for detecting a crank angle (objects for detecting a crank angle) 2a,
2b, 2c and 2d are provided at equal intervals at every 90 °. The crank angle detecting projections 2a, 2b, 2c, 2d
Is set at a crank angle (for example, 10 ° CA before the top dead center of each cylinder) set while the crankshaft of the engine shifts from bottom dead center to top dead center of each cylinder. Further, a cylinder discrimination projection (detected body for reference position detection) 3 is provided on the outer peripheral surface of the signal rotor 1, and this cylinder discrimination projection 3 is not provided following one predetermined crank angle detection projection 2a. They are arranged at equal intervals of 15 °. The cylinder discriminating projection 3 is
It is provided at a predetermined crank angle (for example, 20 ° CA after the top dead center) during the transition from the top dead center to the bottom dead center of one cylinder.

The crank angle detecting projections 2a, 2b, 2
The protrusions c and 2d and the cylinder discriminating protrusions 3 are formed of magnetic material protrusions. Further, each protrusion 2a, 2b, 2c, 2d,
An electromagnetic pickup 4 as passage detection means is arranged near the passage position of the projections 3 and the projections 2a, 2 as shown in FIG.
The passage of b, 2c, 2d, 3 is detected. The electromagnetic pickup 4 is configured by winding a coil (not shown) around a core (not shown) made of a magnetic material. The crank angle detecting projections 2a, 2b,
The passage interval between 2c and 2d corresponds to 180 ° CA, and the cylinder discriminating protrusion 3 corresponds to a position at 30 ° CA after passing through the crank angle detecting protrusion 2a.

An electronic control unit (hereinafter referred to as an ECU) 5 in FIG. 1 comprises a microcomputer 6, a waveform shaping circuit 7, and an A / D conversion circuit 8. The waveform shaping circuit 7 receives the output signal (pickup signal) of the electromagnetic pickup 4 and shapes the waveform of the signal. That is, as shown in FIG.
A pickup signal output from the electromagnetic pickup 4 is binarized by a threshold value Vref to form a pulse signal.

The A / D conversion circuit 8 includes an intake pipe pressure sensor 9
The A / D conversion circuit 8 converts the intake air pressure detection signal (analog signal) from the intake pipe pressure sensor 9 and the engine cooling water temperature detection signal (analog signal) from the water temperature sensor 10 into digital signals. Convert. The microcomputer 6 inputs an output signal of the electromagnetic pickup 4 via the waveform shaping circuit 7 and also receives an intake air pressure detection signal and a water temperature detection signal via the A / D conversion circuit 8. Further, the microcomputer 6 inputs a starter-on signal from the starter motor 11.

The microcomputer 6 includes an injector 1 for each cylinder.
2a, 12b, 12c, and 12d are connected, and each injector 12a, 12b, 12c, and 12d performs a fuel injection operation according to a fuel injection command from the microcomputer 6. An igniter 13 is connected to the microcomputer 6, and ignition is performed by ignition plugs 16a, 16b, 16c, 16d for each cylinder via the igniter 13, the ignition coil 14, and the distributor 15 according to an ignition command from the microcomputer 6.

A battery 18 is connected to the ECU 5 via a key switch 17. When the key switch is turned on, power from the battery 18 is supplied to each device in the ECU 5.

The microcomputer 6 sends the crank angle detecting projections 2a, 2 by the electromagnetic pickup 4 from the waveform shaping circuit 7.
b, 2c, 2d and the passing signal (pulse signal) of the cylinder discriminating projection 3, the time intervals Ti, Ti-1,... between the pulse signals are calculated as shown in FIG. ,
In order to prevent erroneous discrimination, the passage of the cylinder discrimination projection 3 is detected based on the time interval between the three pulse signals to perform cylinder discrimination. That is, as shown in FIG.
from _i and previous sampling values T _i-1 and the second preceding sampling value T _{i-2 Prefecture, T i-2 · T i} / T i-1 2> k1 or not determines. Here, k1 is a discrimination constant (for example, "5").

However, since the cylinder discrimination based on the three information has a problem in the startability, at the time of start (starter is on and before the cylinder discrimination), the cylinder discrimination projection 3 is determined by the time interval between two pulse signals. The passage is detected to determine the cylinder. That is, as shown in FIG. 3, it is determined from the current sampling value T _i and the previous sampling value T _i−1 whether or not T _i−1 / T _i <k2. Where k2 is a discriminant constant (for example,
"0.6"). Further, at the time of starting, as shown in FIG. 2, in order to mask a pulse signal accompanying the passage of the cylinder discriminating projection 3, 1/4 of the 180 ° CA time (= T _i /
4) is a mask section, and when a pulse signal is input within this section, only the cylinder discrimination calculation is performed and the pulse signal is invalidated (indicated by the timing of t1 in FIG. 2).

FIGS. 3, 4, 5, 6 and 7 show pulse signal input states at the start of engine start (starter ON). 3 shows a case where a pulse signal immediately before the pulse signal accompanying the passage of the cylinder discriminating projection 3 is input, and FIG. 4 shows a case where a pulse signal accompanying the passage of the cylinder discriminating projection 3 is input first. FIG. 5 shows the first cylinder discriminating projection 3.
FIG. 6 shows a case where a pulse signal four before the pulse signal accompanying the passage of the cylinder is input, and FIG. 6 shows a case where a pulse signal three before the pulse signal accompanying the passage of the cylinder discriminating projection 3 is input first. Indicates a case where a pulse signal two pulses before the pulse signal accompanying the passage of the cylinder discriminating projection 3 is input first. Then, in FIG. 3, t3 to t8 after the starter is turned on.
The cylinder discrimination based on the two information is established at the timing of and the cylinder discrimination based on the three information is established after the timing of t8. In FIG. 4, cylinder discrimination based on three pieces of information is established after the timing of t7 after the starter is turned on. In FIG. 5, cylinder discrimination based on three pieces of information is established after the timing of t6 after the starter is turned on. In FIG. 6, cylinder discrimination based on three pieces of information is established after timing t5 after the starter is turned on. In FIG. 7, cylinder discrimination based on three pieces of information is established after the timing of t4 after the starter is turned on.

Next, the operation of the control device for an internal combustion engine thus configured will be described. The microcomputer 6 is shown in FIGS.
Shows the processing (flowchart) executed by. This processing is mainly performed before the cylinder determination after the starter is turned on, that is, before t3 in FIG. 3, before t7 in FIG. 4, and t before in FIG.
6 shows output timings of a fuel injection command and an ignition command before t5 in FIG. 6 and before t4 in FIG. FIG. 8 shows a signal input from the electromagnetic pickup 4 when the engine is started (falling edge of a pulse signal).
This is a routine executed every time.

First, the microcomputer 6 executes step 100 of FIG.
Performs the cylinder discrimination processing. FIG. 9 shows details of this processing.
The microcomputer 6 performs cylinder discrimination process by 3 information in step 110 the _{(T i-2 · T i} / T i-1 2> k1).

Then, in step 120, the microcomputer 6 determines whether or not the starter motor 11 is on and whether the cylinder discriminating condition based on the three information or the two information is satisfied. Here, the starter-on determination is for confirming that it is not a so-called push mode in which the vehicle is cranked by pressing the vehicle without using the starter motor 11. If the condition of step 120 is satisfied, the microcomputer 6 increments the actual pulse counter CNIN by “1” in step 130. Further, the microcomputer 6 performs the cylinder discrimination processing (T _i-1 / T _i) based on the two information in step 140.
<K2).

Then, the microcomputer 6 performs a masking process of the additional pulse in step 150. FIG. 10 shows the details of the mask processing. First, the microcomputer 6 determines in step 151 that
Compare the 180 ° CA 1/4 hours and time until the next rise of the pulse signal of the time T _i, a determination is made whether the pulse signal with the passage of cylinder discriminating projection 3 (additional pulses). When the condition of step 151 is satisfied, the microcomputer 6
In step 152, the flag FMS is determined to be not an additional pulse.
Set K to “1”. Then, the microcomputer 6 determines in step 15
At 3, the cylinder counter CNMSK is incremented by "1" and the routine returns. On the other hand, the microcomputer 6 determines in step 151
If the conditions are not satisfied at t6 (t6 in FIG. 4 and t6 in FIG. 5).
5, each of timings t4 in FIG. 6 and t3 in FIG. 7), the flag FMSK is set to "0" in step 154 as an additional pulse, and the process returns.

Incidentally, the initial values are the counters CNIN, CNM
Both SK are “0” and flag FMSK is “1”. This is set when the key switch 17 is turned on for reset or engine stall determination (when the time interval between pulses Ti, Ti-1,... Exceeds a determination value (for example, 200 ms)).

The microcomputer 6 determines in step 200 in FIG. 8 that the actual pulse counter CNIN has an even value of 2 or more (that is, whether two or more pulse signals have been input) and the flag FM
It is determined whether SK is “1” (that is, whether the pulse is an additional pulse). That is, in FIG. 3 to FIG.
It is determined whether or not the pulse trailing edge of the even-numbered pulse after the (th) timing (timing of t1).

If the condition of step 200 is satisfied (t2 in FIG. 3, t2 in FIG. 4,
t4, t2 and t4 in FIG. 5, t2 in FIG. 6, and t in FIG.
2) At step 300, the simultaneous injection processing for all cylinders is performed.
In this method, the fuel injection time (injection amount) is calculated using a table based on the water temperature and correction based on the engine speed NE, and a signal is output in accordance therewith. After the start of injection, the microcomputer 6 determines in step 400 that the cylinder counter CNMSK
Is greater than or equal to 3 and the flag FMSK is not “1” (ie, whether it is an additional pulse), and if the conditions are satisfied (t3, t4, t5 in FIG. 4, and FIG. 5). t
3, t4, t3 in FIG. 6), an ignition process is performed in step 500. This permits the output of an ignition signal having the same shape as the pulse input in synchronization with the next pulse input (t4 ', t5', t7 'in FIG. 4, t4', t7 'in FIG. 5).
t6 ′, t5 ′ in FIG. 6).

On the other hand, the microcomputer 6 performs steps 200 and 4
If the condition is not satisfied in 00, steps 300 and 4
The processes of 00 and 500 are not performed. That is, in FIGS. 3 to 7, if the first pulse falling edge after the starter is turned on (timing of t1 in each drawing), no fuel injection command is issued, and up to the third pulse after the starter is turned on. If the pulse is at the falling edge (at timings t1, t2, and t3 in each drawing), no ignition command is issued.

Thereafter, the microcomputer 6 sets 2 or 3
When the cylinder discriminating condition is satisfied based on the information, an injection command signal and an ignition command signal for each cylinder are output. At this time, the fuel injection time (injection amount) is determined using a map of the engine speed NE and the intake pressure Pm, and is determined by correcting the engine cooling water temperature by the water temperature sensor 10 and the like.

As described above, simply performing cylinder discrimination and mask processing based on two pieces of information at the time of start-up must be performed only when the rotation in the cranking without explosion is stable. When the injection / ignition is started from the pulse signal of
In an operation mode such as explosion → misfire before cylinder identification, malfunction occurs. Therefore, by delaying the start of injection / ignition to a point where there is no effect from the explosion → misfire, reliability and startability are compatible. In other words, after two strokes (360 ° CA) of intake → compression from the start of the injection, it explodes, the rotation rises, then misfires, and the rotation decreases sharply. Before the mistake, the start of the injection is delayed until it can be accurately determined by the three information (the second pulse signal). In addition, after the start of the injection, the ignition is started at the second pulse (two strokes) of the pulse signals of the crank angle detecting projections 2a, 2b, 2c, 2d, so that the mixture in the cylinder before injection at the time of restart of the engine stall. Explosion in the presence of air → misfire can be prevented.

As described above, in this embodiment, the time when only two of the signals are inputted after the passage of the passage signal of the cylinder discriminating projection 3 (detected body) by the electromagnetic pickup 4 (the passage detecting means) after the start of the engine is inputted. Thus, a fuel injection command signal is output to all cylinders of the engine in response to the input of the passage signal, and an ignition command signal is output with a delay of two strokes after the output of the signal. Therefore, by delaying the start of injection until the second pulse input before the position where the entire rotation fluctuation pattern can be captured (3 information cylinder discrimination position), it is not affected by the explosion → misfire, and the injection is prevented. By delaying the start of ignition by two strokes from the start, explosion due to the air-fuel mixture remaining in the cylinder before injection → there is no effect of misfire. As a result, it is possible to reduce the cost by using the same sensor for the reference position and the rotation angle, improve the reliability, and further improve the startability.

The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, in the case of a four-cylinder four-cycle gasoline engine, the fuel injection is started from when two pulse signals are inputted after the starter is turned on. Although the command signal has been output, the start timing (number of pulses) for outputting the fuel injection command signal may be appropriately changed and set according to the number of cylinders and the number of cycles.

[0032]

As described in detail above, according to the present invention,
An excellent effect of achieving both startability and cylinder discrimination is exhibited.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a control device for an internal combustion engine of an embodiment.

FIG. 2 is a diagram for explaining signal processing.

FIG. 3 is a diagram for explaining signal processing.

FIG. 4 is a diagram for explaining signal processing.

FIG. 5 is a diagram for explaining signal processing.

FIG. 6 is a diagram for explaining signal processing.

FIG. 7 is a diagram for explaining signal processing.

FIG. 8 is a flowchart for explaining the operation.

FIG. 9 is a flowchart for explaining the operation.

FIG. 10 is a flowchart for explaining the operation.

FIG. 11 is a time chart for explaining a conventional technique.

FIG. 12 is a time chart for explaining a conventional technique.

FIG. 13 is a time chart for explaining a conventional technique.

FIG. 14 is a time chart for explaining a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Signal rotor 2a, 2b, 2c, 2d Crank angle detection projection as a detection object for crank angle detection 3 Cylinder discrimination projection as a detection object for reference position detection 4 Electromagnetic pickup as passage detection means 6 Microcomputer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02P 5/15 A

Claims (2)

(57) [Claims] 1. A crank angle detecting object provided on a signal rotor which rotates in synchronization with a crank shaft of an internal combustion engine, and an interval following the crank angle detecting object is divided into unequal intervals. The reference object for reference position detection provided in the signal rotor as described above, and a passage detecting means for detecting the passage of the detection object,
A control device for an internal combustion engine, wherein a passage of an object to be detected by the passage detecting means is input and a passage of an object to be detected for reference position detection is detected based on a time interval between the signals. After the detection object passage signal is input by the detection means, the signal is determined by the number of detections required for cylinder discrimination.
A control device for an internal combustion engine, wherein a command signal for injecting fuel into all cylinders of the internal combustion engine is output in response to the input of the detected object passage signal from a point in time when a smaller predetermined number is input. 2. The internal combustion engine control device according to claim 1, wherein an ignition command signal is output from a point in time when a predetermined number of passing signals of the object to be detected for crank angle detection are input after the output of the fuel injection command signal. .